em
PC
2 - 12
-
A500 (
Hardware Manual
)
•
Installation
©
Janz Tec AG
Rev. 1.0
2.2.3 RS485
It is also possible to provide the serial interface as a RS485. Contact the Janz Tec AG for further
information.
In the RS485 variant, there are only the differential signals D+ and D- provided. The transceiver is
enabled to send data, when RTS# of the corresponding UART is low. Data received on the RS485 will
always be seen on the UART’s RxD input. This is regardless of the RTS# state. It is however possible
to modify the hardware, so that transmitted data is not received (RTS# low disables receiver).
When the receiver is enabled and no data is send (MARK=1), then D+ > D-.
2.2.4 CAN
The CAN interface is implemented with a SJA1000 controller chip. The connector is a standard 9 pin
D-SUB plug with a pin out shown in Table 4. The CAN interface is isolated and has a software
switchable 120 Ohm termination.
Pin 1 2 3 4 5 6 7 8 9
CAN n.c. CANL GND n.c. n.c. GND CANH n.c. VEXT
2
Table 4: CAN connector
2.2.5
Power supply, Reset and LEDs
The power supply connector is implemented with a Phoenix Contact Plug type MC1,5/3-ST1F-5,08 BF
and is included in delivery. The assignment of this connector is shown in Figure 6 and Table 5.
Pin
Description
1
+ 9..32 VDC
2
NC, do not connect
3 GND
Figure 6: Power connector
Table 5: Power connector assignment
3
2
1
There is a Reset button next to the power connector. The LED next to the power connector is the
power LED. Additionally there are two more LEDs, S0 and S1. These LEDs are programmable by the
user. The internal GND is connected to the housing the incoming external GND is connected to the via
a common mode choke to the internal GND.
2.3 Compact Flash Removal
Due to space limitations for the
em
PC-A500
, there is no opening in the housing for the
internal Compact Flash card on the CPU module. For removing the Compact Flash card the
housing of the
em
PC-A500
must be opened. Therefore the back panel of the housing must
be removed by removing the four screws – the back is the one with which the
em
PC-A500
is
mounted on the DIN rail.
2
This signal is optionally available to provide power to supply an external transceiver module
Summary of Contents for emPC-A500
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